How small is small? How much do you want to spend? Do you need a XLR DI out? How much tone shaping control do you need? The Fender pedal mentioned above is a lot of pedal for the money - Alex Aguilar designed, I believe - or there's the Xotic BB Preamp, Tonehammer DI, GK Plex, Helix Stomp, Ampeg SCR-DI (although I'd refer this pedal without the Scrambler), amoongst many others. I'd probably start with a Sansamp BDDI though!